diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d2bbe34..42c7226 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -69,6 +69,7 @@
 #include <linux/crash_dump.h>
 #include <linux/tboot.h>
 #include <linux/jiffies.h>
+#include <linux/cma.h>
 
 #include <video/edid.h>
 
@@ -122,7 +123,8 @@
  */
 unsigned long max_low_pfn_mapped;
 unsigned long max_pfn_mapped;
-
+struct cma *crashk_cma = NULL;
+struct cma *crashk_cma_low = NULL;
 #ifdef CONFIG_DMI
 RESERVE_BRK(dmi_alloc, 65536);
 #endif
@@ -532,9 +534,9 @@ static int __init reserve_crashkernel_low(void)
 		return -ENOMEM;
 	}
 
-	ret = memblock_reserve(low_base, low_size);
+	ret =  cma_declare_contiguous(low_base, low_size, 0, CRASH_ALIGN, 0, 1, &crashk_cma_low);
 	if (ret) {
-		pr_err("%s: Error reserving crashkernel low memblock.\n", __func__);
+		pr_err("%s: Error reserving CMA area for crashkernel low.\n", __func__);
 		return ret;
 	}
 
@@ -543,9 +545,7 @@ static int __init reserve_crashkernel_low(void)
 		(unsigned long)(low_base >> 20),
 		(unsigned long)(total_low_mem >> 20));
 
-	crashk_low_res.start = low_base;
-	crashk_low_res.end   = low_base + low_size - 1;
-	insert_resource(&iomem_resource, &crashk_low_res);
+
 #endif
 	return 0;
 }
@@ -578,6 +578,8 @@ static void __init reserve_crashkernel(void)
 						    high ? CRASH_ADDR_HIGH_MAX
 							 : CRASH_ADDR_LOW_MAX,
 						    crash_size, CRASH_ALIGN);
+		pr_info("ronit 0 crash_base %llu crash_size %llu \n", crash_base, crash_size);
+
 		if (!crash_base) {
 			pr_info("crashkernel reservation failed - No suitable area found.\n");
 			return;
@@ -589,30 +591,25 @@ static void __init reserve_crashkernel(void)
 		start = memblock_find_in_range(crash_base,
 					       crash_base + crash_size,
 					       crash_size, 1 << 20);
+		pr_info("ronit base_mentioned crash_base %llu crash_size %llu \n", crash_base, crash_size);
 		if (start != crash_base) {
 			pr_info("crashkernel reservation failed - memory is in use.\n");
 			return;
 		}
 	}
-	ret = memblock_reserve(crash_base, crash_size);
-	if (ret) {
-		pr_err("%s: Error reserving crashkernel memblock.\n", __func__);
+	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
 		return;
 	}
-
-	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
-		memblock_free(crash_base, crash_size);
+	ret =  cma_declare_contiguous(crash_base, crash_size, 0, CRASH_ALIGN, 0, 1, &crashk_cma);
+	if (ret) {
+		pr_err("%s: Error reserving CMA area for crashkernel.\n", __func__);
 		return;
 	}
 
-	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
+	pr_info("ronit halder Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
 		(unsigned long)(crash_size >> 20),
 		(unsigned long)(crash_base >> 20),
 		(unsigned long)(total_mem >> 20));
-
-	crashk_res.start = crash_base;
-	crashk_res.end   = crash_base + crash_size - 1;
-	insert_resource(&iomem_resource, &crashk_res);
 }
 #else
 static void __init reserve_crashkernel(void)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d140b1e..d6a24d6 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -307,7 +307,7 @@ extern size_t vmcoreinfo_max_size;
 
 /* flag to track if kexec reboot is in progress */
 extern bool kexec_in_progress;
-
+extern struct cma *crashk_cma, *crashk_cma_low;
 int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
 		unsigned long long *crash_size, unsigned long long *crash_base);
 int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,
@@ -318,6 +318,13 @@ int crash_shrink_memory(unsigned long new_size);
 size_t crash_get_memory_size(void);
 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);
 
+//custom functions
+int crash_free_memory(unsigned int size);
+int crash_alloc_memory(unsigned int size);
+int crash_alloc_memory_low(void);
+int crash_free_memory_low(void);
+size_t crash_get_memory_size_low(void);
+
 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
 					 unsigned long buf_len);
 void * __weak arch_kexec_kernel_image_load(struct kimage *image);
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 11b64a6..434a8b4 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -39,6 +39,7 @@
 #include <linux/compiler.h>
 #include <linux/hugetlb.h>
 
+#include <linux/cma.h>
 #include <asm/page.h>
 #include <asm/sections.h>
 
@@ -46,7 +47,9 @@
 #include <crypto/sha.h>
 #include "kexec_internal.h"
 
+#define CRASH_ALIGN		(16 << 20)
 DEFINE_MUTEX(kexec_mutex);
+DEFINE_MUTEX(kexec_mutex_low);
 
 /* Per cpu memory for storing cpu states in case of system crash. */
 note_buf_t __percpu *crash_notes;
@@ -57,6 +60,7 @@ u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
 size_t vmcoreinfo_size;
 size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
 
+static struct page *pages, *pages_low;
 /* Flag to indicate we are going to kexec a new kernel */
 bool kexec_in_progress = false;
 
@@ -887,6 +891,17 @@ size_t crash_get_memory_size(void)
 	return size;
 }
 
+size_t crash_get_memory_size_low(void)
+{
+	size_t size = 0;
+
+	mutex_lock(&kexec_mutex_low);
+	if (crashk_low_res.end != crashk_low_res.start)
+		size = resource_size(&crashk_low_res);
+	mutex_unlock(&kexec_mutex_low);
+	return size;
+}
+
 void __weak crash_free_reserved_phys_range(unsigned long begin,
 					   unsigned long end)
 {
@@ -946,6 +961,71 @@ unlock:
 	mutex_unlock(&kexec_mutex);
 	return ret;
 }
+int crash_free_memory(unsigned int size)
+{
+	int ret;
+
+	if (!crashk_cma)
+		return 0;
+	ret = cma_release(crashk_cma, pages, size>>PAGE_SHIFT);
+
+	if (!ret) {
+		pr_info("Crash memory release failed");
+		return 0;
+	}
+	release_resource(&crashk_res);
+	return 1;
+}
+
+int crash_alloc_memory(unsigned int size)
+{
+	if (!crashk_cma)
+		return 0;
+	pages = cma_alloc(crashk_cma, size>>PAGE_SHIFT, KEXEC_CRASH_MEM_ALIGN);
+	pr_info("In crash_alloc_memory fucntion");
+	if (!pages){
+		pr_info("Memory for crash kernel not allocated");
+		return 0;
+	}
+
+	crashk_res.start = page_to_pfn(pages)<<PAGE_SHIFT;
+	crashk_res.end = crashk_res.start + size - 1;
+	insert_resource(&iomem_resource, &crashk_res);
+	return 1;
+}
+
+int crash_free_memory_low(void)
+{
+	int ret;
+
+	if (!crashk_cma_low)
+		return 0;
+	ret = cma_release(crashk_cma_low, pages_low, cma_get_size(crashk_cma_low)>>PAGE_SHIFT);
+
+	if (!ret) {
+		pr_info("Crash low memory release failed");
+		return 0;
+	}
+	release_resource(&crashk_low_res);
+	return 1;
+}
+
+int crash_alloc_memory_low(void)
+{
+	if (!crashk_cma_low)
+		return 0;
+	pages = cma_alloc(crashk_cma_low, cma_get_size(crashk_cma_low)>>PAGE_SHIFT, KEXEC_CRASH_MEM_ALIGN);
+	pr_info("In crash_alloc_memory fucntion");
+	if (!pages){
+		pr_info("Low memory for crash kernel not allocated");
+		return 0;
+	}
+
+	crashk_low_res.start = page_to_pfn(pages)<<PAGE_SHIFT;
+	crashk_low_res.end = crashk_low_res.start + cma_get_size(crashk_cma_low) - 1;
+	insert_resource(&iomem_resource, &crashk_low_res);
+	return 1;
+}
 
 static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
 			    size_t data_len)
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index e83b264..fbc5314 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -116,12 +116,23 @@ static ssize_t kexec_crash_size_store(struct kobject *kobj,
 {
 	unsigned long cnt;
 	int ret;
+	int size;
 
 	if (kstrtoul(buf, 0, &cnt))
 		return -EINVAL;
 
-	ret = crash_shrink_memory(cnt);
-	return ret < 0 ? ret : count;
+	size = cnt<<20;
+	if (cnt == 0) {
+		crash_free_memory_low();
+		ret = crash_free_memory(crash_get_memory_size());
+	}
+	else if (cnt > 0) {
+		if (crash_get_memory_size_low() == 0)
+			crash_alloc_memory_low();
+		ret = crash_free_memory(crash_get_memory_size());
+		ret = crash_alloc_memory(size);
+	}
+	return count;
 }
 KERNEL_ATTR_RW(kexec_crash_size);